In aircraft frames, the main propulsions engines not only provide propulsion but the bleed air is recirculated and used to drive a variety of rotating parts such as a generator, compressor, or pumps and further supply both electric and pneumatic power to the aircraft system. However, when the aircraft is grounded its main engine(s) may not be running, and auxiliary power units (“APU”) are used to provide aircraft systems power and/or start propulsion systems and engines.
These aircraft are often operated in a variety of environments and climate which enable high concentrations of dust and particulates to be captured with the inlets. These particulates when ingested within are captured in the fluid flow of the APU decrease efficiency and adversely affect performance. For example, these particulates or foreign object debris (“FOD”) can corrode and/or erode the interior passageway and parts within a turbine plug apertures within a cooled combustor. To alleviate this debris from entering the aircraft, procedures such as “FOD walk-down” are implemented to capture any debris along the runaway before being sucked into the turbines or APU's.
To overcome these challenges, many aircraft have included particulate separators, vortex panels, and multi-channel particulate separators. However, each of these designs is often difficult to maintain and may not be readily cleaned or installed between uses.
Though there are a variety of filtering devices and systems available within the public domain such as U.S. Pat. No. 3,970,439 to Murphy; or U.S. Pat. No. 3,778,983 to Rygg, these references fail to disclose a particulate filter for an auxiliary power unit which may be easily assembled/disassembled and cleaned between uses.